Leg lifts help A TON! just have a family member or someone stand up and then you lay down on your back and grab their ankles. have them push your legs so they almost touch the ground. then try and raise them back up. Repeat this 25 times around 10 times a day and in a month I bet you that you'll see dramatic changes!
You could do squats and sit ups and raising your feet while standing keeping on your toes
Download the app 'Zombies, Run!' app on iTunes. I kid you not, this app is amazing. You use it when going for a run, with headphones in, and it makes sounds as if zombies are running behind you and you have to run away. I downloaded it because I was willing to use anything to get fit and I actually love it! It makes me freak out and I sprint faster and further, and then when I'm really exhausted, I simply just remove the headphones and take a 1 minute break. To make your legs slimmer, I highly recommend squats. You can also download the 'Daily Ab Workout FREE' app, it is an ABSOLUTE KILLER but it definitely helps to tone your stomach. If you do have a bit of extra weight on your tummy that you want to get rid of, it's a good idea to go running to lose that, in conjunction with stomach exercises :)